Subsections

- Library
- Description
- Dialog Box
- Default properties
- Interfacing function
- Computational function (type 1)

##
Discrete state-space system

### Library

Linear

### Description

This block realizes a discrete-time linear state-space system. The system is defined by the matrices and the initial state . The dimensions must be compatible. At the arrival of an input event on the unique input event port, the state is updated.

### Dialog Box

Set discrete linear system parameters |
A matrix | -1
B matrix | 1
C matrix | 1
D matrix | 0
Initial state | 0

- A matrix: square matrix. TheA matrix
- B matrix: theB matrix
- C matrix: the C matrix
- D matrix: theD matrix
- Initial state : vector. The initial state of the system.

### Default properties

- always active: no
- direct-feedthrough: no
- zero-crossing: no
- mode: no
- number/sizes of inputs: 1 / 1
- number/sizes of outputs: 1 / 1
- number/sizes of activation inputs: 1 / 1
- number/sizes of activation outputs: 0 /
- continuous-time state: no
- discrete-time state: yes
- name of computational function: dsslti

### Interfacing function

`scilab/macros/scicos_blocks/linear/DLSS_f.sci`

### Computational function (type 1)

          subroutine dsslti(flag,nevprt,t,xd,x,nx,z,nz,tvec,ntvec,
         &     rpar,nrpar,ipar,nipar,u,nu,y,ny)
    c     Copyright INRIA

    c     Scicos block simulator
    c     discrete state space linear system simulator
    c     rpar(1:nx*nx)=A
    c     rpar(nx*nx+1:nx*nx+nx*nu)=B
    c     rpar(nx*nx+nx*nu+1:nx*nx+nx*nu+nx*ny)=C
    c
          double precision t,xd(*),x(*),z(*),tvec(*),rpar(*),u(*),y(*)
          integer flag,nevprt,nx,nz,ntvec,nrpar,ipar(*)
          integer nipar,nu,ny
          double precision w(100)
    c
    c
          la=1
          lb=nz*nz+la
          lc=lb+nz*nu
          if(flag.eq.4) then
             if(nz.gt.100) then
                flag=-1
                return
             endif
          elseif(flag.eq.2) then
    c     x+=a*x+b*u
             call dcopy(nz,z,1,w,1)
             call dmmul(rpar(la),nz,w,nz,z,nz,nz,nz,1)
             call dmmul1(rpar(lb),nz,u,nu,z,nz,nz,nu,1)
          elseif(flag.eq.1.or.flag.eq.6) then
    c     y=c*x+d*u
             ld=lc+nz*ny
             call dmmul(rpar(lc),ny,z,nz,y,ny,ny,nz,1)
             call dmmul1(rpar(ld),ny,u,nu,y,ny,ny,nu,1)
          endif
          end